code: def on_mouse_press(self, event):
      self.idx = (self.idx + 1) % 32
  
file_path: vispy/examples/demo/gloo/voronoi.py
imports: import numpy
  from vispy import app
  from vispy import gloo
label_desc: Use image node_id 6 for calling the Canvas obj's underlying member method code with example usage: obj.on_mouse_press(event) without return types